1-How would you create your own custom view?
By Subclassing the UIView class.
2-Whats fast enumeration?
Fast enumeration is a language feature that allows you to enumerate over the contents of a collection. (Your code will also run faster because the internal implementation reduces
message send overhead and increases pipelining potential.)
3-Whats a struct?
A struct is a special C data type that encapsulates other pieces of data into a single cohesive unit. Like an object, but built into C.
4-What are mutable and immutable types in Objective C?
Mutable means you can change its contents later but when you mark any object immutable, it means once they are initialized, their values cannot be changed. For example, NSArray, NSString values cannot be changed after initialized.
5-Explain retain counts.
Retain counts are the way in which memory is managed in Objective-C. When you create an object, it has a retain count of 1. When you send an object a retain message, its retain count is incremented by 1. When you send an object a release message, its retain count is decremented by 1. When you send an object a autorelease message, its retain count is decremented by 1 at some stage in the future. If an objectʼs retain count is reduced to 0, it is deallocated.
6-Whats the difference between frame and bounds?
The frame of a view is the rectangle, expressed as a location (x,y) and size (width,height) relative to the superview it is contained within. The bounds of a view is the rectangle, expressed as a location (x,y) and size (width,height) relative to its own coordinate system (0,0).
7-Is a delegate retained?
No, the delegate is never retained! Ever!
8-Outline the class hierarchy for a UIButton until NSObject.
UIButton inherits from UIControl, UIControl inherits from UIView, UIView inherits from UIResponder, UIResponder inherits from the root class NSObject
9- What is dynamic?
You use the @dynamic keyword to tell the compiler that you will fulfill the API contract implied by a property either by providing method implementations directly or at runtime using other mechanisms such as dynamic loading of code or dynamic method resolution. It suppresses the warnings that the compiler would otherwise generate if it can’t find suitable implementations. You should use it only if you know that the methods will be available at runtime
10-If I call performSelector:withObject:afterDelay: – is the object retained?
Yes, the object is retained. It creates a timer that calls a selector on the current threads run loop. It may not be 100% precise time-wise as it attempts to dequeue the message from
the run loop and perform the selector.

iOS Interview Questions Part-2

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